1. Technical Field
The present invention relates to a stereo image processing device for a vehicle that processes an image captured by a stereo camera unit installed on the vehicle and three-dimensionally recognizes a traveling environment.
2. Related Art
The technique of capturing a traveling environment in front of a vehicle with a camera and recognizing the traveling environment by image processing has recently found application in vehicles such as automobiles. In particular, various types of driver assist control methods such as collision avoidance with respect to forward obstacles, tracking control with respect to a vehicle in front, and warning control and steering control relating to wobbling and lane departure have been implemented by using a stereo image processing technique of capturing the same object with a stereo camera from different visual points and three-dimensionally recognizing the object from the parallax (distance data) obtained.
Such a stereo camera unit is configured, for example, by mechanically fixing a pair of cameras with a predetermined base line (distance between optical axes) such that the optical axes thereof are substantially parallel, and where the mounting position thereof is shifted, the image capturing directions of the cameras are shifted, the vehicle in front cannot be recognized, and the accuracy of distance data is degraded.
For this reason, Japanese Unexamined Patent Application Publication No. 2004-132870 (JP 2004-132870 A) discloses the technique for improving the reliability of distance data by disposing an adjustment chart in front of a stereo camera unit, processing the captured image of the adjustment chart, and adjusting the displacement of the stereo camera unit.
However, with the conventional technique such as disclosed in JP 2004-132870, the presence of a stereo camera displacement is examined and the adjustment is performed on a stationary vehicle during inspection at a production plant upon shipping of the vehicle or at a maintenance site such as a dealership, and it is difficult to determine whether or not displacement has occurred in a stereo camera unit under the actual usage conditions.